1. Field of the invention
This invention relates generally to the field of crop agriculture and more particularly to means for providing eradication of harmful viticulture microorganisms.
2. Description of Prior Art
The established viticultural practice for eliminating vineyard microorganisms in its most prevalent form as a fungus and its means of reproduction by spores has been to apply liberal doses of fungicides by broad coverage spraying techniques using spray applicators.
The infection of green tissue, flower clusters and buds by spores results in fungal diseases common to the grape family and most agricultural crops. When spore infection occurs conidia are produced and the disease spreads rapidly throughout the vineyard. The spread of disease is enhanced if the combination of temperature, leaf wetness and time are satisfied. Some of the fungal diseases that attack grapes in particular are: (1) Powdery Mildew, (2) Downey Mildew, (3) Black Rot, (4) Phomopsis Cane and Leaf Spot, (5) Eutypa Dieback.
The sprayers are drawn through the vineyard rows with tractors which may also supply the power to drive the spray pumps. Various spray fungicides are applied at periodic intervals. Generally these intervals are 10 to 14 days but may become shorter resulting in more frequent applications during rainy or high humidity seasons.
The use of pesticides has become frought with problems for the grape grower due to their chemical nature, the necessary safety precautions required, government regulations and the consumers reluctance to eat produce treated with pesticides. The spray operator, for his own safety, is required to wear protective clothing, a special breathing mask, eye goggles and water proof gloves to prevent contamination by toxic pesticides. Present fungicides work in the following manner:
a. The fungicide is absorbed within the plant tissue (the fungicide is systemic) or provides a protective coating on the surface.
b. It acts as an protectant to prevent infection, or if the plant is already infected it acts as an eradicant to stop infection or as an antisporulant to prevent disease spread.
Turning now to a brief consideration of a specific disclosure of interest, U.S. Pat. No. 1,876,737 issued to F. W. Opp on Sept. 13, 1932 discloses an apparatus for the ray treatment of vegetation. This patent was directed primarily to destroying parasitic life specifically with high voltage electrical rays (X-Rays) for the treatment of trees. It is also known to use infra red or colored lights in the visible spectrum for the purpose of stimulating or controlling growth of plants, their seeds or increasing fruit set, as disclosed for example in U.S. Pat. Nos. 2,300,727, 3,372,513, 3,931,695, 4,041,642, and 4,506,474. None of the above mentioned references relate to the treatment of plants or vineyards with apparatus using Ultraviolet energy in the germicidal band for its proven fungicidal action.